If I’m interpreting your post correctly my legs go through this as well. Not sure why but, I attribute old age and maybe just generally not cycling enough. This will sound like BS but, I’ve had some interesting results helping to fix the problem with AMP Human PR lotion (used to be called Topical Edge). I use it for harder rides/races and even recovery now. Look into the product and make up your own mind. It’s basically sodium bicarbonate…Link: https://amphumanperformance.com/